Association of the Single-Nucleotide Polymorphism rs6265 of the Brain-Derived Neurotrophic Factor Gene with Features of the Clinical Pictures of Parkinson’s Disease

Objective. To assess the frequency and severity of various clinical manifestations of Parkinson’s disease (PD) depending on the rs6265 polymorphism of the BDNF gene. Materials and methods. The study involved 533 patients with PD. PD staging was assessed using the Hoehn and Yahr scale and the severity of motor impairment using the MDS-UPDRS. Non-motor impairments of PD were assessed using validated questionnaires and scales: the Beck Depression Inventory II, the Hospital Anxiety and Depression Scale, the Apathy Scale, the Montreal Cognitive Assessment Scale, and the Questionnaire for the Assessment of Obsessive-Compulsive Disorders in Parkinson’s Disease Rating Scale. Genotyping of the polymorphic variant of the BDNF gene (rs6265) was performed by real-time PCR using TaqMan probes. Results. Most patients with PD had a combination of non-motor symptoms, the number of these symptoms increasing as the disease progressed and being determined by the individual’s molecular genetic characteristics. Statistically significant differences in the severity of motor and non-motor disorders were found: individuals with the AA genotype were found to have significant motor disorders (p < 0.0001), along with emotional-affective (p < 0.0001), cognitive, and impulsive behavioral disorders (p < 0.0001). Conclusions. The study showed that the rs6265 BDNF (A) allele is associated with a wide range of non-motor symptoms, increasing the risk that they will develop in PD patients, and therefore playing an important role in the pathogenesis of this pathology.